Recent years have seen a rapid increase in the amount of data available to a user via data network coupling to remote server, with cheap browser packages for home personal computer (PC) users and dedicated (and cheaper) access mechanisms such as WebTV greatly increasing the number of people on-line. A number of examples of network access and server systems, whether for the Internet or on a smaller local area network (LAN), are described in the introduction to EP-A-0 732 660 (Kambayashi et al/Toshiba) which relates to a mechanism for providing a degree of personalisation in service provision.
In the system described, a number of client systems (for example home users) are enabled to access, via network, data stored by a server. Each of these users is registered with the server having provided to it certain personal details such as an e-mail address and/or telephone number and optionally also a photograph. In operation, when a user is accessing a particular store or field of data held by the server, the server provides to the user a list of those other users concurrently accessing the data, perhaps providing an on-screen display of the photographs of those registered users.
As the number of people using networks such as the Internet continues to grow, so the extended use of individual telephone lines will create more problems. If a person is on-line then others cannot call them and even other on-line users cannot communicate in an immediate way using the Internet unless both parties go to a dedicated “chat space”—a host environment where messages may be exchanged. E-mail has been found to have problems with reliability and speed and, in view of the increasing volumes of electronic “junk mail” users are receiving, there is no guarantee that a message will be read once received.
The main difficulty with communication between two or more concurrently on-line users on such as the Internet is that if they make use of a dial-up connection then their Internet Protocol (IP) address—the numeric address that addresses each packet—will be different each time they connect. Specially written or modified chat software will not be able to handle the establishing of a link as one on-line person does not know the IP address of another for dial-up accounts on many Internet service providers.
It is therefore an object of the present invention to provide a means by which on-line users may be alerted to someone attempting to contact them.